Golf practice apparatus



Feb. 6, 1962 A. L. M NEILL GOLF PRACTICE APPARATUS Filed Oct. 31, 1957FIG. I

9 Sheets-Sheet l INVENTOR Alvin L. MC Neill BY fm W Wm l flk ATTORNEYSFeb. 6, 1962 A. L. M NEILL 3,020,049

GOLF PRACTICE APPARATUS Filed Oct. 31. 1957 9 Sheets-Sheet 2 FIG. 5

\ l l l I l l l i INVENTOR. Alvin L. Mc Neill 98 M, WW1, WQW +1 ATTORNE5 Feb. 6, 1962 A. L. M NEILL 3,020,049

GOLF PRACTICE APPARATUS Filed Oct. 31, 1957 9 Sheets-Sheet 3 INVENTOR.

Y Alvin L. McNeiH p MLQWrT ATTORNEYS 9 SheetsSheet 4 Filed Oct. 31, 1957Feb. 6, 1962 A. McNElLL GOLF PRACTICE APPARATUS 9 Sheets-Sheet 5 FiledOct. 51, 1957 INVENTOR. BY Alvin L. Mc Neill GWWWQMMCFQW ATTORNEYJ' Feb.6, 1962 A. L. M NEILL 3,020,049

GOLF PRACTICE APPARATUS Filed Oct. 31, 1957 9 Sheets-Sheet 6 we leoINVENTOR.

Alvin L. Mc Neill ziTTORNEYS Feb. 6, 1962 A. McNElLL GOLF PRACTICEAPPARATUS 9 Sheets-Sheet '7 Filed Oct. 31, 1957 in mi NE 2.

INVENTOR. Alvin L. Mc Neill MWQ Y ATTORNEYS Feb. *6, 1962 A. McNElLL cowPRACTICE APPARATUS 9 Sheets-Sheet 8 Filed Oct. 51, 1957 INVENTOR BYAlvin McNeill {3 MMQM W ATTORNEYS N J 3 H H 333:3 r

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Feb. 6, 1962 A. MCNEILL 3,020,049

GOLF PRACTICE APPARATUS Filed 001;. 31, 1957 9 Sheets-Sheet 9 INVENTOR.

BY Alvin L. Mc Neill NW W Wqgm '1 W ATTORNEYS Patented Fehfi, 1962 FiledOct. 31, 1957, Ser. No. 693,670 4 Claims. 01. 273-486) This inventionrelates to golf practice apparatus and more particularly to suchapparatus of simplified form capable of giving to the user thereof avisual indication representative of the distance, direction and qualityof his stroke, i.e., of the distance to which, the direction in which,and straightness with which an actual golf ball might have been drivenby his stroke.

In accordance with the invention a captive golf ball or ball simulationis provided to be struck by. theplayer with a golf club. Electricalapparatus associatedwith this ball measures the impact with which it isstruck. This impact is a measure of the maximum distance to which a freegolf ball struck with such impact might travel. Associated with theimpact measuring appara tus, in suitably spaced relation to the captiveball, there are provided means to develop signals representative of thedirection and shape of the players' swing. Signals thus representativeof the direction and shape of the swing are then combined with theimpact signals in electrical apparatus to select on a display board avisual display which is energized to indicateto the player the nature ofhis stroke.

In contrast with various proposals heretofore made for inferring therange, direction of flight, and hook or slice component in a golf strokeby means of a dummy ball supported with separate degrees of freedom foreach of these attributes of the stroke and by mean of sensing apparatusresponsive to the motion of the dummy ball in each of these degrees offreedom, the present invention employs for the ball simulation a'si'mpleform of mounting which measures impact only. The direction in which andthe straightness with which the golfers stroke would drive an actualball are, in accordance with the present invention, judged by signalsdeveloped by the club head during portions of its swing other than thatoccupied by contact with the ball simulation. The signals representativeof the shape of the swing are employed in display signal selectingcircuits to select one or another display signals in accordance with thedeparture of the shape of the swingso measured from an optimum shape andfrom a normally preferred direction.

The invention will now be further described with referrence to theaccompanying drawings in which:

FIG. 1 is a perspective view of one form of golf drive practiceapparatus according to the invention;

FIG. 2 is a fragmentary plan view of the platform in the apparatus ofFIG. 1 on which the player stands to strike the ball, showing thearrangement with respect to the ball of the means for measuring thedirection and shape of the play'ers swing;

FIG. 3 is a plan view of the captive ball and of associated elementsdisposed within the platform of FIG. 1 for developing signalsrepresentative of the impact with which the ball is struck;

FIG. 4 is a sectional view taken on the line 4-4 of FIG. 3;

FIG. 5 is a diagrammatic view in section of one of the swing measuringelements seen in plan in FIG. 2;

FIG. 6 is an enlarged fragmentary view of the display board of theapparatus of FIG. 1; 1

FIG. 7 is a sectional view taken on the line 77 of FIG. 6, shown at anenlarged scale;

v FIG. 8 is a fragmentary diagrammatic view of the display board of theapparatus of FIG. 1 showing the form of certain of the display circuitstherein;

FIG. 9 is a diagram indicating the relation to each others of FIGS. 10,11, 12 and 13; and

FIGS. 10 to 15 together form a schematic wiring diagram of theelectrical components of the apparatus of FIG. 1.

The golf practice apparatus of FIG. 1 comprises a platform generallyindicated at 2, above which appears a ball simulation 4, supported onand fastened to a stem 6. The stem is mounted on and fastened to aresilient support as illustrated in FIG. 4 and extends up througha'slot-l'ike opening indicated at 8 in the upper surface of theplatform. The user of the apparatus stands upon the platform 2 andstrikes the ball simulation with a golf club, exactly as in the mannerof actual play.

A display board generally indicated at 10 in FIG. 1 gives to the user ofthe apparatus, substantially as soon as he has struck the ballsimulation, a visual indication of the power and quality of his stroke,by means of a combination of mechanical and electrical elementshereinafter to be described. After a suitable time interval thisindication is extinguished, and the entire apparatus is prepared for themaking of another stroke. Apparatus according to the invention may, forexample, be provided in placeslof public amusement, where a coinapparatus generally indicated at 9, connected to the platform 2 by acable 11, permits a player to purchase a specified number of strokes inreturn for a coin inserted into the apparatus 9.

There is further seen in FIG. 1 a plate 12 set into the upper surface ofplatform 2 and over which the head of the users golf club passes duringthe follow-through portion of his swing after striking the ballsimulation 4. The plate 12, seen in plan in FIG. 2, is of transparent orpartially transparent nature and accordingly permits the casting by theclub head of a shadow on one or more of a plurality of light sensitivedevices 14- disposed in two linear arrays 18 and 20 within the platform2 beneath the plate 12. These light sensitive devices 14 each comprise,in a presently preferred embodiment of the invention, a photocell 16with a surrounding opaque light refleeting cone 17, as indicated in FIG.5. The cone 17 is provided to enlarge, beyond the size which would bespecified by the dimensions of the light sensitive electrode in thephotocell, the cross-sectional area or column of space between theplatform and a bright lamp 13, disposed above the platform 2,interception of which by the club head will generate a signal in thephotocell. Lamp 13 is connected to platform 2, and more particularly toa complex of electrical apparatus housed in the rear thereof andpresently to be described, by means of a cable 15. While the perspectiveof FIG. 1 prevents its being so shown, lamp 13 is preferably disposeddirectly over the plate 12.

As indicated in FIG. 2, the light sensitive elements 14 are disposed intwo linear arrays or rows 13 and 20, advantageously arcuate in shape,and so positioned with respect to the rest position of the ballsimulation 4 (also shown in FIG. 2) that on a normal swing "by thegolfer employing the apparatus, a signal will be generated by one of thelight sensitive elements in each of the two rows 18 and 20. The twolight sensitive elements thus excited to produce signals are a measureof the quality of the golfers swing, in particular of the initialdirection of flight which an actual ball in the position of the ballsimu-'. lation 4 would follow on leaving the tee comprising platform 2and also of the straightness or trueness with which the ball would havetraveled in such direction, as indicated by the shape and curvature ofthe projection onto the plane of the platform of the path followed bythe club head during the golfers follow-through swing.

spasms The cones 17 (FIG. 5) are so dimensioned and the light sensitivedevices 14 containing them are so spaced apart in each of the arcuaterows 18 and 20 that the shadow cast by the golfers club head during theinitial follow-through portion of his stroke (e.g., until the club headrises to the level of the players waist) will obscure illumination ofthe photocell in one and only one of the elements 14 of such rowsufficiently to generate a signal, which will trigger into conduction anelectronic circuit into which such photocell is coupled. One suchcircuit, presently to be described, is provided for each of the elements14. p p

In this fashion two signals are generated, representative of thepositions at which the club head shadow crosses rows 18 and 20. Thesesignals together, by referenceto the rest position of the ball 4,provide information on the direction in which an actualball wouldhavebeen driven by the stroke being evaluated and also of the quality ofthat stroke. I

Referring to FIG. 2, there is shown at a dash line 22 the path of thecenter of the shadow of the club head on a stroke such as would drive anactual .ball, teed 'at the position of the ball simulation 4, in thestraight ahead. direction indicated by the line 24. Thisfstraight aheaddirection is that which the golfer naturally strives to achieve, itbeing parallel to the sides of, the platform 2 and generallyperpendicular to the display board 10, It will be noted that the path 22is curved, being substantially the projection onto the plane of theplatformjof the initial part of the follow-through portion of theplayers stroke. In FIG. 2 the elements 14 are individually identifiedwith reference characters P1 to P14, and it is seen that a true,straight aheadstroke of whatever impact is the result of a swing whosefollow-through'produces signals at elements P4 and P11., I, 1 V

The apparatus of the invention distinguishes a large number of two-cellcombinations which can be triggered by the club head, including one cellfrom each row. It distinguishes for example the combinations P4, P andP4, P12 as departures from the optimum stroke which triggers thecombination P4, P11. In addition the apparatus distinguishes, amongothers, the combinations P3, P10; P3, P9; P3, P11 and the combinationsP5, P12; P5, P11; P5, P13. 1

The board 10 is fragmentarilyillustrated,infplanand sectional views, inFIGS. 6 and 7, and a further partial diagrammatic showing thereof iscontained in FIG. 8. For clarity, FIG. 8 shows only thelowercentralportion of the board, and shows in that portion the displaysassociated with the lower values of impact only. The board comprises alarge rectangular sheet of opaque material 26 pierced with a largenumber of holes 28. An electric lamp 30 is positioned behind the boardat each of these holes to cast its light thercthrough, and these lampsare connected together into a plurality of separately energizablecircuits each containing a plurality of lamps, each lamp belonging toone circuit only.

The lamps of each circuit are positioned at holes in the board whichmake up a line extending, generally, from the midpoint of the lower edgeof the board'up the board a distance and in a direction generallyrepresentative of the stroke being represented according to the combinedeffect of the impact value measured and to the conformity of thefollow-through portion of the stroke to an optimum follow-through swingpattern for a given direction .as determined by the light sensitiveelements in rows 18 and (FIG. 2) triggered by the club head shadow.

Part of such a circuit or string of lamps is shown in FIG. 6, where alllamps 30 shown are energizable in parallel from a cable 32, shown indashed lines in view of its representation in phantom in thatfigure.

As indicated in FIG. 7, the opaque sheet 26 may be overlaid with atransparent sheet 34 of glass or the like, on which a pictorialrepresentation ofa golf course or portions thereof may be applied. Inthis connection, the

lamp at the upper end of the string, or of certain of the strings, maybe disposed behind an enlarged hole 28', to permit illumination therebyof a golf green painted on the transparent sheet 34.

The invention provides on the board 10 a number of distinct lampcircuits. In the presently preferred embodiment of the invention nowbeing described, this number is substantially equal to the product of aplurality of distinguishable impact values or impact ranges and a numberof distinguishable combinations of light sensitive elements among theelements P1 to P14 of FIG. 2. As will be further explained inconjunction with FIG. 8, the number of lamp circuits can be widelyvaried consistently with the invention.

The relationship ,to each other of the lamp circuits associated withagiven range of impact values measured at the ball simulation and ofthese circuits with those associated with the adjacent range of impactvalues is illustrated in FIG. 8,. FIG.,'8 is a schematic view of thedisplay board showing the lower central portion thereof and showinginthat portion the shape and position of the strings of lamps 30 for twoadjacent ranges of impact values. ,The circuits'associated with thelower range of impacts are indicated at full lines identified byreference characters T5 to Tl2 while those associated with thehigherrange of impacts are indicated at dashed lines identified byreference characters T18 to T25. In the embodiment illustrated, all lampcircuits include lamps arranged in a pattern, l ineor string originatingat the mid-point at the lower. edge of the board and extendinggenerally. upward therefrorn. Each of the circuits T5 to T12 andTld toI25 isenergized by a stroke having one ort'he other of the adjacentranges of impact measured atthe ball 4 and each will be energized bysuch a stroke, the follow-through portion of which generates signals ata particular combination of the light sensitive elements P1 to'PIfl asfollows:

Display board lamp circuit Combination of light sensitive elements 14Lower Higher range of range of impact impact values values T5 T18 T6 T19T7 T20 T8 T21 T9 T22 T10 T23 T11 T24 Ti] T24 T12 T25 T12 T25 Still othercombinations of the elements 14 are actuable by the players club headafter striking the ball 4, and their actuation leads, according to theimpact value of the stroke, to the energization of still other lampcircuits on the board 10. These have however for clarity been omittedfrom FIG. 8.

For any given stroke, the element of row 18 which is actuatedidentifiies generally the direction of flight which a free ball sostruck would take, whereas the combination of elements in rows 18 and 20indicates the straightness or trueness with which such a free ball wouldtravel. More particularly, the elements P P together with the restposition of ball 4 define an are which conforms to the projection ontothe plane of platform 2 of the path of the club head when swung toproduce a straight shot parallel to the edges of the platform. Hence inFIG. 8 the circuits T9 and T22 are straight and are oriented parallel tothe vertical sides of the board. The combination P P however representsthe arc of the projection 'of a club trajectory on a stroke withexcessive effort or snap" in the players wrists. Such a stroke, appliedto a free ball, would cause that ball to rotate counter-clockwise asseen from above and would hence produce a hooked shot. The correspondinglamp circuits T8 and T21 are accordingly laid out on the board 16 torepresent hooked shots. Conversely the combination P P represents astroke with insuificient snap in the wrists, the club head being pulledby the player. Such a stroke would cause clockwise rotation of a freeball as seen from above and would hence produce a sliced shot, and thecorresponding lamp circuits T and T23 are laid out on the board in thecurved shape of a sliced ball. The hook or slice quality of a golfstroke is thus according to the invention inferred from the trajectoryof the club head, and is displayed to the player by a correspondingshaping of the display board lamp circuits. The direction of the shot isalso displayed by an orientation on the board of the lamp circuits inaccordance with the identity of the element in row '18 which producestheir energization. It will thus be noted that the combination P Penergizes the lamp circuits T6 or T19 disposed to the left of circuitsT8, T9 and T10 or T21, T22 and T23 respectively, all of which areproduced by photo-cell combinations including element P in row 18.

The board 10 of FIG. 1 includes lamp circuits for still other ranges ofimpact values and combinations of photocells 16. It also includescertain auxiliary lamp circuits. One of these illuminates, whenenergized, a 'rectangular opening 36 at the lower edge of the board overwhich may be applied on the transparent sheet 34 the word Play, thiscircuit being energized when the apparatus is ready for a stroke.Another of these illuminates a cutout 37 in sheet 26 over which isapplied the word Duff or the like, indicating a stroke below passinggrade, as when the players follow through swing fails to actuate a lightsensitive element in one of the two rows 18 or 29, or in both.

The board may incorporate still other lamp circuits.

A description will now be given of the components by means of which theboard is energized at one of the lamp circuits thus far described. Theimpact measuring apparatus is illustrated in FIGS. 3 and 4. The stem 6of the ball simulation, which in the assembled apparatus projectsthrough the slot 8 in the platform 2,, is supported and fixed at itslower end in a resilient elastic support 40. The support 40 comprises ahollow inverted body of rubber or the like, approximately conical inshape, which may be advantageously filled with elastic material inspongy form, for example the closed cellular plastic commonly known asStyrofoam. The rubber member is provided at its lower edge with a flangeover which fits a metallic ring 42. Cap screws passed through the ring22 and flange securely hold the flange to a base plate 46, fixed inposition within the platform 2 of FIG. 1. The base plate prevents thecontents of member 46* from being expelled therefrom, thus increasingthe elastic resistance which member 40 presents to any deflection ofstem 6 from a vertical position.

Two sides plates 4'6 are affixed to plate 46, one on each side of member4t and a member 50 having tensile resiliency such as a strand of rubberis strung between them in stressed relation, with anchor points on thetwo side plates so positioned that with the ball simulation 4 at restits stem 6 stretches the member 50 into a shallow J shape. A bar 52between side plates 48 supports a microswitch 54 in such position thatits actuating member 56 is engaged by resilient member 50 when the ballsimulation is at rest, keeping the switch open in the particularembodiment of the invention being described. When the ball is struck,deflecting stem 6 from the vertical position shown in FIG. 4, strand 50permits switch 54 to close, thus generating a signal.

In front of the ball simulation, in the sense in which it is supportedin the platform 2, the base plate 46 supports a microswitch 53 beneath apad 60 of resilient material. The actuating member 620i switch 58 isarranged to be actuated, to generate a second signal, whenever the pad61 receives a blow from the ball 4, which is driven to a horizontalposition when struck by the players golf club, and which then whips backto the vertical. The time interval between the actuation of switches 54and S8 is a measure of the impact with which the ball is struck. The pad60 serves both to protect the switch 58 from excessive shock and toinsure its actuation irrespective of the position at which the ballreaches the plane of pad v6t), within a range of positions ample for thepurpose.

The successive signals generated upon actuation of switches 54 and 58are conveyed by cables 63 and 64 to the display board lamp circuitselecting apparatus, presently to be described. This apparatus isadvantageously housed immediately in back of the display board, in anenclosure forming part of the display board structure. In view of theshort time intervals involved and the use of these signals for thecontrol of vacuum tubes, the cables 63 and 64 may advantageously be ofcoaxial type. In the embodiment of the invention here being described,switch 54 is closed when the ball simulation is struck by the playersclub head, and switch 58 is closed when the ball simulation strikes pad60.

There will now be described by reference to FIGS. 1014 the electricalcomponents of the apparatus of FIG. 1 by means of which the impactsignals from the apparatus of FIGS. 3-4 and the signals from lightsensitive elements P1 to P14 are combined to effect energization of aparticular, appropriate one of the lamp circuits on board 10.

FIG. 10 is a diagram of a power supply provided'for energization of theelectrical components of the golf drive apparatus of FIG. 1. Also shownin FIG. 10 is the coin operated timer 9 of FIG. 1. The coin operatedtimer 9 includes a switch 66, adapted to be closed upon insertion of asuitable coin, and an electric motor 68.

Motor 68 has coupled thereto a gear train which, after an interval ofoperation of motor 68 (for example of the order of a few minutes)operates to reopen'switch 66. Switch 66 effectively governs energizationof the entire apparatus so far as concerns its utility to the player oruser. Coin timer 9 is connected to the remainder of the electricalsystem by cable 11.

Input power to the entire electrical circuit may be derived from anordinary 110 volt A.C. lighting circuit through conductors 70 and 72 andfuses 74. With conductors 7t} and 72 energized, power is supplied tothree transformers 80, $52 and 84. One winding 86 on transformerenergizes the filaments of all vacuum tubes in the system and also thecoil of a thermal relay 87 through a normally closed contact 192-1 on arelay K102. When relay 87 operates, relay K162 is energized, opening itscontact 102-1 and closing its normally open contacts 192% and 1il2-3.

Another winding 88 on transformer 80 provides voltage to conductors S9and 90 and thence, via control and switching circuits presently to bedescribed, to the lamp circuits on the display board. Transformer 80includes another secondary winding 92 to which is connected a full waverectifier 881 as shown. One of these provides a negative voltage toconductor 94 from which various negative bias voltages are developed atconductors 94, 96, 98, and 102. The other provides, upon energization ofrelay K191, positive 13+ voltage at conductor 104. Lower positiverectifier voltages are derived therefrom at conductors 106 and 108.Voltage regulator tubes may be provided as indicated in the drawing forstabilization of these voltages.

The voltage from transformer 32 is applied to the filaments of two hotcathode grid controlled gas rectifiers or thyratron tubes V203 and VZM(FIGS. 11 and 12). The voltage from transformer 84 is applied (viaconductors 83 and 85) to a special circuit shown in FIG. 15

li which indicates to the player the number of strokes remaining to himand which may have other functions.

Two conductors 110 and 112 connected through normally open contact 101-1of relay K101 to conductors 70 and 72 constitute a reset circuit forrestoring the apparatus to a condition preparatory to renewed play, whenthe allotted time runs out by operation of motor 68.

Energization of relay K101 opens the reset circuit at normally closedcontact 101-1 and closes normally open contact 101-2, thereby completingthe circuit for the rectifier 881 whose output conductor is shown at104. Referring to FIG. ll, conductor 104 is seen to apply B+ voltage toa wiper arm 120-1 of a stepping switch generally indicated at 120.

Stepping switch 120 may have a plurality of banks of stationarycontacts, one being indicated in FIG. 11 and two others being shown, inthe embodiment illustrated, in P16. 15. FIG. 11 shows a first bank ofthese contacts and the associated wiper arm 120-1. The stationarycontacts of the bank shown in FIG. 11 are divided into odd and evennumbered contacts, all odd numbered contacts being short-circuitedtogether to a conductor 124 and all even numbered contacts beingshort-circuited together to a conductor 126. A total of twenty-onestationary contacts may be provided in each bank. For clarity, however,only one odd and one even contact are shown in FIG. 11.

Stepping switch 120 having been restored by its reset coil 123 and byconductors 110 and 112 via contact 101-1 in FIG. 10, wiper arm 120-1rests on the number one stationary contact of the bank illustrated inFIG. 11, so that B+ voltage is applied from conductor 104 to conductor124 and to a relay K211, energizing the same. The circuit of conductors110, 112 and reset coil 128 is completed at a contact 129 mechanicallylinked to wiper arm 120-1 to be closed except when that arm is in itsfully reset position. Resetting may take place upon energization of coil128 through a mechanical spring and latch mechanism not shown, inaccordance with the usual operating of stepping switches.

On relay K211 a normally open contact 211-1 is now closed, grounding aresistor R223 (FIG. 12) to permit discharge of a capacitor C212 Whosefunction will be presently described. A normally closed contact 211-2 isopened by energization of relay K211, thus removing the short circuit toground across a capacitor C201 in the grid circuit of a cold cathode gastube V201.

In addition, energization of relay K211 opens a normally closed contact211-3, disconnecting conductor 106 and its regulated stabilized positivevoltage from a conductor 136 and from the plate of a thyratron tube V204(FIG. 12). Lastly, energization of K211 grounds at a normally opencontact 211-4 a conductor 137 and therewith the grid of a thyratron tubeV207 through a resistor R227 and through a normally closed contact 130-3on a second stepping switch generally indicated at 130, this contactbeing mechanically coupled to the rotating wiper arm 130-1 of thatswitch to be opened only when switch 130 is at reset position, as shownin FIG. 12.

With relay K211 energized, the control grid of V201 rises above groundas C201 charges through R201 and after a short time delay, which may beof the order of one second, this produces conduction in the tube V201and consequent energization of a relay K201 whose coil is in the platecircuit of that tube. This closes a normally open contact 201-1 whichcompletes the circuit for the stepping coil 121 on switch 120, shiftingthe wiper arm 120-1 thereof from an odd to an even numbered stationarycontact. With this shift in the condition of relay 120, relays K201 andK211 de-energize and a further relay (202 is instead energized viaconductor 126 from the even numbered stationary contact. Since steppingcoil 121 is now open-circuited relay 120 remains stationary after a onestep shift from an odd to an even stationary contact, relay K206 nothaving been energized.

On relay K202 a normally open contact 202-1 is now closed, completing,through a normally closed contact 203-3 on a de-energized relay K203(FIG. 12) the volt circuit from conductors 70 and 72 for an overheadlight or projector 13 (FIG. 1) which illuminates the light sensitiveelements 14 in platform 2 of FIG. 1. Closing of 202-1 also energizes thelamp of a Play sign 134 which may be provided in the display board atopening 36 (FIG. 8) or elsewhere, indicating to the user of theapparatus that it is ready for use. A second normally open contact 202-2on relay K202 also closes and applies B+ voltage from conductor 104 tothe plate of a thyratron type tube V203.

With relay K202 energized and positive voltage on the plate of tubeV203, the system is ready to measure and to evaluate a practice golfstroke. Tube V203 is biased off on its grid with a low negative voltagefrom conductor 100 but is brought into conduction by means of a positivepulse produced when the golfers club head strikes the ball 4. Theinstant when the club head strikes the ball may be referred to as time tAt this instant microswitch 54 is shifted from the grounded positionshown in FIG. 11 to a contact 55 at B+ and a positive pulse is thusgenerated and applied through cable 63 to a capacitor C206 in the gridof V203, causing that tube to conduct.

The ultimate effect of such conduction is to initiate conduction in adiode V206A (FIG. 12) to charge a timing capacitor C212 through a chargelimiting resistor R220 in the cathode circuit of a thyratron V204 whichis brought into conduction by conduction in V203 and which has appliedto its plate a regulated positive voltage from conductor 106 through thenow closed contact 211-3 on deenergized relay K211 and conductor 136.

More particularly, firing of tube V203 energizes a relay K209 to apply aregulated positive voltage from conductor 106 to the plates of two tubesV202A and V2028, each of which is connected in a modified Miller circuitfor production of a delayed signal as will be presently described.

Firing of thyratron tube V203 additionally applies the positive voltageof conductor 104, reduced by the drop in that tube, to conductor 190 andthrough a neon glow tube 138 to the grid of a further thyratron tubeV204. This tube is caused to conduct, it now having positive platevoltage applied thereto in view of the de-energized condition of relayK211. Regulated positive voltage is then communicated through tube V204to the plate of a diode-connected tube V206A in whose cathode iscontained the capacitor C212 which functions to measure the impact valueof the stroke.

Firing of V203 also applies positive voltage via conductor 190 to relaysK204, K205 and K203. These relays remain de-energized however inasmuchas the circuits for the actuating coils thereof remain incomplete inFIG. 13, these circuits being first completed by operation of a steppingswitch of that figure during the evaluation of the stroke by means ofthe light sensitive elements 14 of FIGS. 1 and 2.

Capacitor C212 charges in an exponential or approximately linear fashionuntil the ball simulation 4 strikes impact pad 60 (FIG. 4) and shiftsthe second microswitch 58 to its positive contact 59 (FIG. 11). Thisproduces a second positive pulse which is conducted through cable 64 toa conductor 142 and thence through a capacitor C211 and resistor R221(FIG. 12) to the grid of a further thyratron tube V205. V205 is biasedoff through resistors R230 and R231 and through a chain of resistorsR232-R238 associated with the stationary contacts of one bank instepping switch 30. Resistors R232-R238 lead to the negative bias supplyat conductor 96.

The stop pulse produced at microswitch 58 thus initiates conduction inV205. It follows the start" pulse of microswitch 54 with a time delayrepresentative of the impact imparted to the ball. Conduction in tubeV205 initiated by the stop pulse effectively grounds the plate of diode206A and consequently terminates the charging of capacitor C212. Theinterval between the start and stop pulses typically amounts to a fewmilliseconds, whereas the time constant of the discharge circuit forcapacitor C212 provided by resistor R224 is long by comparison therewithand furthermore long by comparison with the actual operating time of thestepping switch 130. This stepping relay operates to assume an angularposition representative of the initial charge value in capacitor C212within the time short compared to the discharge time constant.

The voltage to which capacitor C212 is charged is reproduced across aresistor R225 in a cathode follower circuit comprising tube V206B. Thevoltage thus reproduced is applied to a network including resistor R226,the grid of a thyratron V207, R229, the wiper arm 130-1 of one bank onswitch 130, and so many of resistors R232-R238 which lead to thenegative bias at conductor 96 as are not bypassed by arm 130-1. In theabsence of a positive voltage charge on C212 anda consequent positivevoltage across R225, thyratron V207 is negatively biased beyond cutoff,even for the positive voltage excursions imposed on its plate by meansof a transformer T201 whose secondary is inserted in series with theplate of that tube in a circuit including the actuating coil 132 ofstepping switch 130. The primary of transformer T201 is fed with anappropriately proportioned alternating current voltage which mayadvantageously be the power line voltage as reduced in amplitude bytransformer 86 of FIG. 10. In series with coil 132 there is provided acontact 133, coupled mechanically to wiper arm 130-1 to open at eachstep made by the latter.

The rest or reset position of stepping switch 130 is that illustrated inFIG. 12, in which the Wiper arms 130-1 and 130-2 of its two banks are inthe position shown in the drawing, arm 130-1 applying minimum negativebias to tube V207. With the positive voltage across R225 produced by thecharge stored in C212, however, the bias on tube V207 is reduced to suchan extent that the tube is caused to fire on the positive excursions ofits plate. Accordingly, pulses of current are passed by tube V207 atpower line frequency, and stepping switch 130 shifts its wiper arms onestep for each such pulse until the increasing negative voltage tapped bythe wiper arm 130-1 increases the negative bias on tube V207 to a pointat which the tube no longer fires.

The second bank of contacts on relay 130 includes stationary contactsconnected to a plurality of impact lines or conductors 1 -1 which areconnected respectively to the wiper arms 150-2 to 150-7 of the second toseventh banks 152-157 (FIG. 14) of a stepping switch 150 shown in FIG.13. It is through the stationary contacts of these banks that areenergized the various lamp circuits on the display board such as thecircuits T to T12 and T18 to T25 of FIG. 8. The wiper arm 130-2 ofstepping switch 130 is connected via conductor 16% to a normally opencontact 204-2 in relay K204 and, upon closure of that contact andenergization of relays K203 and K205, to a conductor 89 of the lampcircuit transformer winding 88, conductor 90 being grounded (FIG. 11).

With maximum impact the interval between the start and stop pulses is aminimum and the charge stored during that interval in C212 is also aminimum. Consequently, stepping relay 130 will move through a minimumnumber of steps in response to such a stored charge, so that the line ofmaximum impact I in the second bank of stepping relay 130 is thatcorresponding to a single step for that relay away from the restposition shown in the drawings. Conversely, the minimum impact line Icorresponds to a maximum number of steps of that relay.

The impact of the stroke having been measured, there now remains for theapparatus of the invention to evaluate the direction and quality of thestroke or swing shape in order to select on the display board a lampcircuit representative of the combined factors of impact, direction andquality. The components illustrated in FIGS. 12, 13 and 14 together withthose already described, cooperate to this end.

Each of the photocells 16 of the array of light sensitive elements 14 ofFIG. 2 is, as shown in FIG. 5, provided with a grounded cathode and withan anode connected through a current limiting resistor R331 to a sourceof positive voltage at conductor 108. in addition the anode is connectedthrough a capacitor C313 t0 the grid of one of the thyratron tubesV301-V314 of FIG. 13, all of which are biased off at conductor 98. FIG.5 illustrates this connection between the element P1 and V301. Thephotocells of light sensitive elements P1 to P6 of row 18 in FIG. 2, arethus connected to thyratrons V301 to V306 respectively in FIG. 13,whereas those of elements P7 to P14 are similarly connected tothyratrons V307 to V314 respectively.

When the head of the gol-fers club passes over the row 18 of photocellunits in FIG. 2, the illumination from the lamp 13 is substantially cutoff from one of the photocells in that row and conduction therein ismomentarily extinguished or sharply reduced. This produces a positivepulse of voltage which is communicated to the corresponding one ofthyratrons V301-V306. This tube is then brought into conduction.Conduction in any of tubes V301-V306, wvhose cathodes are grounded,completes via a conductor 160 the circuit for relay K204. Energizationof K204 closes a normally open contact 204-1 on that relay. Thisextends, via conductors 176 and 178, from open contact 203-1 on relayK203 to open contact 205-1 on relay K205, a circuit which, whencompleted by energization of relays K203 and K205 will energize steppingswitch 150.

Energization of relay K204 also closes a normally open contact 204-2which connects the wiper arm -2 on the second bank of stepping relay 130to a normally open contact 205-3 on relay K205. Upon closure of contact205-3 the lamp circuit for the display board will be completed, exceptfor an open contact 203-2 on relay K203, from conductor 89 (FIG. 11) towiper arm 130-2 and the lamp circuit selector bank of stepping relaytowhich arm 130-2 is connected by one of lines 1 to 1 This connection ismade by a conductor 164 between.

203-2 and 205-3, a conductor 166 bet-ween 205-3 and 204-2, and conductor168 between K204-2 and wiper arm 130-2.

When the club head intercepts the light incident on one of the photocellunits in the second row indicated at 20 in FIG. 2, the corresponding oneof the thyratron tubes V307-V314 is energized, completing the circuitfor energization of relay K205 via a conductor 162. When this relay isenergized, a first normally open contact 205-1 thereon is closed tocomplete the driving circuit for the actuating coil 159 of steppingswitch 150 from conductor 94 in FIG. 11 to ground at a normally closedcontact 208-1 on relay K208 except for the open contact K203-1 on relayK203.

Simultaneously, a normally closed contact 205-2 is opened to isolate thenegative bias line conductor 93 from the less negative bias line 102 inthe power supply. This increases the negative bias applied by conductor98 to the unfired thyratron tubes in the series V301 to V314 in order toprevent energization of any additional ones of those tu-bes when theshadow of the club head sweeps back across the arrays of photocells asthe club head rises above the players waist on the follow-through, orwhen he returns the club head to the vicinity of the ball 4.

A further normally open contact 205-3 on relay K205 is closed uponenergization of that relay to connect the lamp circuit conductor 164from relay K203 via conductor 166 back into relay K204 Where, if relayK204 has been energized, it will be completed via conductor 168 into thewiper arm 130-2 in stepping switch 130. The normally closed contact205-4 on relay K205 connects conductor 164 to a conductor 170 forillumination of the dad shot cutout 37 on the display board as anindication of a bad or incomplete stroke. It will be observed that bythe provision of a conductor 172 between normally closed contacts 204-3and 205-4, provision is made for energization of the duff shot conductor170 upon energization of K203 in place of the conductor 163 leading tothe lamp circuits T1 to T54 in the event that either K204 or K205 orboth should fail to be energized by the players follow-through swing.

Assuming a signal to be generated at a light sensitive element 14 ineach of rows 18 and 20, one thyratron in each of the groups V301-V30fiand V307-V314 will have been brought into conduction, and both of relaysK204 and K205 will be energized, all within a space of time no more thansome 25 or 50 milliseconds after t the time of first contact of the clubhead with the ban simulation 4. The lamp circuit on the display boardrepresentative of the impact value, direction and quality of the playersstroke has been potentially identified, the impact value in terms of thecharge on C212 and the direction and quality in terms of the particularcombination among the thyratron tubes V301-V314 which has been broughtinto conduction. Within a time of the order of 100 or 150 millisecondsafter t relay 130 has evaluated the charge on C212 in terms of aparticular final angular position for wiper arm 130-2, connectingconductor 168 to a particular one of lines I to 1 The energization ofthe lamp circuit on the display board is next eifected by stepping relay150 upon the energization of relay K207 when conduction in tube V202-Breaches the threshold of excitation of that relay. Tube V202-B istypically adjusted to energize relay K207 within some 500 millisecondsafter time t i.e., well after switching relay 130 has come to rest. Whenrelay K207 energizes, it produces energization of relay K203 bygrounding conductor 174 at contact 207-1. Contact 203-1 then closes andcompletes the driving circuit for stepping relay 150 from conductor 94through contact 203-1, conductor 176, contact 204-1, conductor 178,contact 205-1, conductor 180, actuating coil 159 of relay 150, conductor182 and contact 208-1 to ground. Contact 203-2 also closes and completesthe lamp circuit from conductor 89 to conductor 168. Opening of normallyclosed contact 203-3 extinguishes the projector lamp 13 and Play sign134, while opening of normally closed contact 203-4 opens the connectionof the low negative bias conductor 102 into 205-2.

Stepping switch 150 now commences to rotate its wiper arms. This relaycomprises a plurality of banks of stationary contacts. All wiper arms inswitch 150 move together and occupy the same angular position withrespect to the stationary contacts of their banks. In the embodimentillustrated in the drawings, there are a total of eight banks, eachcontaining twenty-one contacts, the first and last being generallyindicated at 151 and 158 in FIG. 13. The stationary contacts in banks151 and 158 are connected in combinations as shown in FIG. 13 to theplates of tubes V301 to V314, the contacts of bank 151 being associatedwith tubes V301 to V306, whereas the contacts of bank 158 are associatedwith tubes V307 to V314. Wiper arm 150-1 of bank 151 is connected by aconductor 186 to one of the actuating coiis 208-2 of relay K208, theother terminal of that actuating coil connecting through an adjustableresistor R208 to conductor 190 which leads to the cathode of V203.Similarly, wiper arm 150-8 is connected by a conductor 13% to the secondactuating coil 208-3 of relay K208, the other terminal of this coilconnecting through adjustable resistor R207 to conductor 190. Thearmature 208-4 of relay K208 is so adjusted by means of resistors R207and R208 that conduction is required in both of coils 208-2 and 203-3be- 12. fore contact 208-1 will open and before contact 208-5 willclose.

In connection with the stationary contacts of banks 151 and 158 to tubesV301-V314, the arrangement is such that for each of the angularpositions to which the wiper arms of switch 150 can move, there is oneand only one pair of thyratron tubes (each such pair including a tubefrom the group V301-V306 and one from the group V307-V314), for whichthe wiper arms 150-1 and 150-8 of both of banks 151 and 158 will beconnected to ground by conduction in tubes of the series V301-V314.Relay 150 will accordingly move stepwise until this condition is arrivedat, its wipers, which move together, beginning from the stationarycontacts where the relay was left by previous operation and movingcounterclockwise in FIG. 13. When wiper arms 150-1 and 150-8 are bothgrounded through conducting tubes in the series V301- V314, both ofcoils 203-2 and 200-3 carry current, and relay K208 will energize.Upening of contact 208-1 breaks the circuit for the stepping coil 159 ofrelay 150, and the wiper arms accordingly move no further.

Normally open contact 208-5 closes when relay K203 energizes, and inclosing grounds a conductor 192 in the common path of all of the displayboard lam circuits. This is indicated for a typical lamp circuit in FIG.14.

Referring now to FIG. 14, there are generally indicated at 152 to 157the six intermediate banks of stationary contacts of stepping switch150, together with the wiper arms 150-2 to 150-7 thereof. Each of thesewiper arms is connected to one of the conductors I to I of FIG. 12. Thestationary contacts on banks 152-158 are connected into a plurality oflamp circuits T1 to T54 on the display board. One of these is shown atT1, one terminal of the circuit T1 connecting to all stationary contactsin bank 152 and the other terminal connecting (as with all of circuitsT1 to T54) with conductor 192 of FIG. 12 for grounding when relay K208energizes. The other lamp circuits T2 to T54 are indicated in FIG. 14only by reference to the stationary contact or contacts of banks 152 to157 at which they respectively begin. It is also seen in FIG. 14 that byconnection of all but one of the stationary contacts in bank 157 to thewiper arm of bank 156, strokes of impact value resulting in selection ofline i at relay energize the same display board lamp circuits as strokeswhich generate signals at the same combinations of light sensitiveelements 14 (FIG. 2) but with the next lower range of impact values,except in the case of the perfect shot or stroke which produces signalsat elements P4 and P11 and which consequently brings stepping switch torest with its wiper arms on their eleventh stationary contacts. In thiscase, a separate board lamp circuit T54 is energized. This may comprisethe board lamp circuit T48, brought into conduction by a relay which isenergized by circuit T 54, plus a number of additional lamps lengtheningthe string on the board 10.

A large number of possibilities exist for the selection and arrangementof such lamp circuits. In the embodiment illustrated in FIG. 14, all ofthe stationary contacts in bank 152 connect to the single lamp circuitT1, this being a lamp circuit not shown in FIG. 8. This means that ifthe player strikes the ball 4 so fcebly that maximum time is requiredbetween the production of start and stop pulses at microswitches 54 and58, the signal displayed on the board, to indicate minimum performance,is made without discrimination as to either direction or quality ofswing. If the ball is struck hard enough to result in selection ofimpact lines I at relay 130, any one of twelve lamp circuits T2 to T14may be selected on the display board according to the angular positionto which relay 150 moves before being brought to a halt by theenergization of a particular combination of tubes in the seriesV3-01-V314. Of these, circuits T5 to T12 are shown in FIG. 9, lampcircuits T2, T3, T5, T11, T12,

13 and T13 being each energized for two angular positions of relay 150.

In similar fashion impact values corresponding to impact lines I I, andI permit illumination on the display board of any one of three groups oflamp circuits T15 to T27, T28 to T40 and T41 to T53.

The lamp circuit so energized on the display board continues illuminateduntil conduction in tube V202-A rises to the threshold level of relayK206 in the cathode thereof. When this relay is energized, its contacts206-1 complete the circuit for the stepping coil 121 in stepping relay120, shifting the wiper arm 120-1thereof from an even contact (numbertwo, in case only a single play has been had) to the next succeeding oddnumbered stationary contact. This shift de-energizes relay K202 withconsequent extinctionof tube V203, and de-energization of relay K209 andof all the remaining relays and thyratrons in the system,-while relayK211 becomes energized. Stepping switch 130 is thereby reset to its zeroor number one stationary contact position by conventional mechanicalelements (not shown) forming part thereof. Relay 150 is not reset butremains in the position to which it was moved by the stroke whosedisplay has just ended.

Approximately one second'later V201 is brought to conduction again withenergization of relay. K201, and relay 120 is shifted'once more to aneven contact. This results in relighting of the projector lamp 13,,andthe system is again ready for another stroke.

The last even numbered stationary contact in the first bank of switch120 is isolated from relay K202, so that the player has a limited numberof strokes for his coin. With the completion of the timeinterval-established by the gear train coupled with the timer motor,switch 66 is opened, 'whether or not all plays have been completed, andK101 is deenergized. This opens the B+ circuit of conductor 104 andprevents further operation of the equipment. At the same time, thecircuit for the reset coil of switch 120 is completed at contact K101-1and stepping switch 120 is restored to its zero position in which thewiper arm is on the number one contact.

There will now be described, with reference to FIG. 15, still otherfeatures forming a part of the invention in the preferred embodimentthereof.

The components already described provide a completely operative-golfpractice apparatus according to the which is not connectedto conductor126, the apparatus is effectively disabled until reset by timer motor68.

It is, however, advantageous to give to the player a running count ofthe number of strokes which he has taken, or of which remain to him tobe taken. Moreover, the interest in the apparatus can be heightened bydesignating, for successive strokes, particular ones among the displayboard lamp circuits as targets or objectives to be achieved. Componentssuitable to these ends are schematically illustrated in FIG. 15.

In FIG. 15 there are shown at 120-2 and 120-3 the wiper arms of thesecond'and third banks of contacts on stepping switch 120. These banksare generally indicated at 123 and 125 respectively. Associated witheach of these wiper arms are a plurality of stationary contacts,twenty-one in the embodiment illustrated, and the wiper arms are shownon the first stationary contacts of their respective banks, all theseWiper arms 120-1, 120-2, 120-3 moving together upon operation ofstepping switch 120. The even numbered stationary contacts in bank 123,beginning with the fourth, are seen to be connected to one terminal of aplurality of lamps L9 to L1, while the first and last (twenty-first)contacts are connected to one terminal of a lamp L10 which mayilluminate a Pay sign 39 on the board 10 (FIG. 8). Wipers 120-2 and120-3 are connected to conductor 83 of transformer 84, while theopposite terminals of lamps 14 L1 to L10 are all connected to the otherconductor of that transformer.

When the entire apparatus is reset by de-energization of relay K101,restoring wipers -2 and 120-3 to the positions shown therefor in FIG.15, and also when they engage their twenty-first or last stationarycontacts, lamp L10 is lighted.

With a suitable coin inserted into the timer, the wiper arms of switch120 shift to their second stationary contacts upon energization of relayK201. The player, in the example being described, now has ten strokes tomake, or to go. Upon his striking the ball 4, tube V202-A measures otf atime interval during which the board is illuminated with a displayrepresentative of the stroke just made, and when relay K206 energizesswitch 120, it advances its wiper arms to their third stationarycontact. Again a short delayis-imposed by tube V201 until relay K201,energizes, and stepping relay 120 advances to its fourth numberedstationary contacts. The apparatus is now set up for the next stroke,and: lamp L9 is lighted, indicating that there are nine strokes to go.Thus, each time wiper arm 120-2 shifts to an even numbered stationarycontactfthe apparatus is-set up for a stroke, and the number of strokesremainingto be taken is indicated to the player; After the tenth .strokehas been taken, and also after the apparatus is reset, the Pay lamp L10is tighted. For this purpose lamps L1 to L10 may advantageously beprovided in the display board itself, for example, at an aperture 36"out of 'the area occupied by the lamp circuits T1 to T54.

Bank of stepping relay 120 and the other com: ponents illustrated inFIG.15 supply the apparatus of FIG. 1 with the otheroptional features nowunder consideration, which may for convenience be termed a fchallengecircuit or circuits.

On the board, and advantageously adjacent the ends of a plurality ofselected ones of the lamp circuits T1 .to T54 representative of ballsfairly hit with adequate impact, there may be provided challenge ortarget lamps or combinations of lamps 300, 302 and 304 (FIG. 15). One ofthese is also shown at 300 in FIG. 6. One terminal of each of these isconnected to conductor 85. The other terminals of these lamps areconnected via movable -9 contacts respectively to normally closedcontacts 306-3, 308-3 and 310-3 of three relays K306, K308 and K310respectively. These relays are provided with mechanical latches whichlatch the movable contacts thereof in the position opposite that shownin the drawing when energized, and they are provided respectively withreset or release windings 312, 314 and 316, all connected in parallel-toconductors 318 and 320 which, as indicated in FIG. 11, connect to theopposite terminals of reset coil 128 on stepping switch 120.

Display board 10 is provided with additional lamps or lamp combinations322, 324, 326 (FIG. 15) which may be disposed immediately adjacent lamps300, 302 and 306 respectively, but arranged to be distinguishabletherefrom. Thus lamps 300, 302 and 304 may be positioned behindtransparent sheet 34 of board 10 to illuminate representations ofgolfgreens, whereas lamps 322, 324, and 326 when lighted illuminaterepresentations of flags. Lamps 322, 324 and 326 have each one terminalconnected to a movable l0 contact engageable with either a normallyclosed 4 contact or with a normally open -5 contact on relays K306, K308and K310 respectively, and the other terminal connected to a movable -11contact engageable with either a normally closed. 6 or a normally open 7contact on those relays respectively.

Further, for each of lamps 300, 302 and 304, conductors 328, 330 and 332respectively lead from a normally closed -4 contact on relays K306, K308and K310 respectively to the stationary contact or contacts of banks 152to 157 of stepping'relay (shown in FIG. 14) of the display board lampcircuits with which the chal- :lengecircuitof lamps 300, 302 and 304 are"respectively associated. Thus if the lamp circuit illustrated in FIG. 6is T31, with which challenge lamp 300 and flag lamp 322 are associated,conductor 328 connects to the sixth and seventh stationary contacts ofbank 155 in FIG. 14. Conductors 328, 330 and 332 also connectrespectively through normally open contacts 302-1, 303-1 and 304-1 onrelays K302, K303 and K304 with the actuating coils of relays K306, K308and K310 respectively. Relays K302, K303 and K304 have their actuatingcoils connected between conductor 85 on the one hand and both of the -1and 3 normally closed contacts on relays K306, K308 and K310respectively.

Further conductors 334, 336 and 338 lead respectively to movable contactblades 8 on relays K306, K308 and K310 respectively, these contactblades being engageable with normally closed -1 and with normally open-2 contacts of those relays in respectively, in their de-energized andenergized states respectively. Moreover, conductor 336 connects withnormally open contact 306-2. Similarly, conductor 338 connects withnormally open contact 308-2.

Conductor 334 is connected to the second, eighth and fourteenthstationary contacts in bank 125, and conductor 336 to the fourth, tenthand sixteenth, and conductor 338 to the sixth, twelfth and eighteenthand twentieth. Accordingly, when stepping relay 120 advances its wiperarms to .the second stationary contact in each of its banks, conductor334 will be energized.

Application of voltage to conductor 334 results in energization of relayK302 via contact 306-1 on relay K306. It also lights the target orchallenge lamp 300 via contact K306-3. The operator of the apparatus nowmakes his stroke. If he is successful in the objective manifested bylighting of lamp 300 he will cause relay 150 to select for energizationon the display board the lamp circuit T31. Energization of this, andonly this, lamp circuit applies voltage to the conductor 328 in FIG. 15.This produces energization of relay K306 via the now closed contact302-l. When relay K306 is energized, it latches and its movable contacts306-10 and 306-11 effect illumination of the flag lamp 322, indicatingto the player that he has succeeded, and, as it were, made a hole inone. Energization of relay K306 moreover extinguishes challenge lamp 300and de-energizes relay K302.

Advance of stepping relay 120 to its fourth numbered stationary contactfor the next stroke produces at bank 125 energization of conductor 336with a similar sequence of events respecting challenge or target lamp302 and flag lamp 324 in case the player achieves selection of theparticular lamp circuit on the display board to whose contact orcontacts among the stationary contacts of banks 152-157 conductor 330 isconnected. Similarly, preparation in stepping relay 120 of the thirdstroke by advance of its wiper arms to their sixth stationary contactsproduces energization of conductor 338 with lighting of target lamp 304.

FIG. illustrates a particular detail in the embodiment illustrated towhich reference has already been made. The optimum form of stroke isthat which in the array of light sensitive elements of FIG. 2 producessignals at elements P4 and P11, and this results in advance of steppingrelay 150 to its eleventh numbered stationary contact in all banks. Fora stroke of impact value identified with conductor I of stepping relay130 this produces energization of the lamp circuit T48 on the displayboard. This circuit includes a plurality of lamps connected between theeleventh stationary contact in bank 156 of relay 150 and conductor 192of FIG. 11 exactly in the manner illustrated in FIG. 13 for lamp circuitT1. In addition, however, there is shown in FIG.

15 a conductor 340 which is connected at one end to the eleventhstationary contact in bank 156 of FIG. 14, i.e., at the end of lampcircuit T48 opposite conductor 192. Conductor 340 is connected at itsother end to the movable contact 301-1 of a relay K301. In thedeenergized condition of this relay a blade 301-1 thereof engages astationary contact 301-2. Contact 301-2 connects to one terminal of alamp or combination of lamps 342, the other terminal of which isconnected to conductor 192 of FIG. 12. Lamp 342 illuminates on displayboard 10 a yardage marker, for example, one reading 270 yards toindicate to the player that he has made a very good stroke. Lamp 342 isthus a supplement to circuit T48, illuminated when the latter isenergized from impact line I If, however, the stroke to be displayedproduces signals at the same light sensitive elements P4 and P11 butwith even higher impact which causes relay to step only to the impactline I of highest impact, it will be wiper -7 in bank 157 of FIG. 14which is energized for illumination of a lamp circuit on the displayboard. Consequently, voltage will be applied to the eleventh stationarycontact of bank 157, this contact being that which produces energizationof lamp circuit T54.

Lamp circuit T54 comprises a conductor 344 shown in FIG. 14 and thecontinuationof which is shown in FIG. 15. Conductor 344 connects at oneterminal with a lamp or lamp combination 346, the other terminal ofwhich connects with conductor 192. It also connects with one terminal ofthe actuating coil of relay K301, the other terminal of that actuatingcoil also connecting with conductor 192.

Consequently, upon application of voltage to conductor 344 relay K301 isenergized and its movable contact 301-1 engages a normally open contact301-3 thereon to which conductor 344 is also connected.

In consequence, application of voltage to conductor =344 energizes thelamp circuit T48, via conductor 340, and, in addition, the yardagemarker lamp 346 which may, for example, be labeled "300 yards.

It will be seen from the foregoing that the invention provides golfpractice apparatus comprising, among other components, a captive ball 4,displaceable means 6 to support the ball in a rest position, first andsecond microswitches 54 and 58 arranged to be actuated successively bysaid support means upon striking of the ball with a golf club swungthereat, a capacitor C212 connected in series with a resistor R220, witha third switch constituted by tube V204 and with a source of directcurrent voltage at conductor 136. The invention further provides in tubeV203 means to close that third switch in response to actuation of switch54 and in tube V205, means to open that third switch in response toactuation of switch 58. The invention also provides a first steppingrelay switch 130 having a plurality of contacts in each of two banks, afirst electron discharge device V207 having a cathode, anode and controlgrid and having its anode-cathode path connected in series with thestepping coil 132 of that stepping switch and with a source ofalternating current voltage at transformer T201. The invention furtherprovides a plurality of resistors R232 to R236 connected in series withthe contacts of one of those banks, these resistors being connected inseries with a source of direct current voltage at conductor 96 and witha further resistor R225 to bias said device V207 to cut off. Theinvention further provides in tube V2068 means to apply a voltagerepresentative of the charge on capacitor C212 as an unbiasing signal tothe control grid of device V207 whereby the stepping switch 130 willtake up a position representative of the value of that charge. Theinvention further provides a display board 10, a plurality of lampcircuits T1 to T54 arranged in groups on that board, and a plurality offirst supplementary lamp circuits 300, 302 and 304 and secondsupplementary lamp circuits 322, 324 and 326 arranged on that board inassociation with certain of said first named lamp circuits, e.g. withcircuits T31, T48 and T35. The invention further provides a secondstepping relay switch 120 having a plurality of banks of contacts andhaving odd spasms and even numbered contacts of one bank thereofconnected together respectively. The invention further provides in relayK211 means operable by said second steppingswitch to permit charge ofsaid capacitor C212 upon actuation of said first switch when said secondstepping switch is on an even numbered contact and to discharge saidcapacitor when said second stepping switch is on an odd numberedcontact. The invention further provides two linear arrays 18 and 20 ofphotoelectric sensing elements 14.,eXtendin'g transversely of the pathof the shadow of the club head on the plane of platform 2 in position tobe traversed successively by that shadow, the elements being arrangedfor the generation of a signal at one element in each of those arrays bythat shadow. The invention further provides (in tubes V301-V314) anelectron discharge tube for each of the elements 14, these tubes havingan anode, a cathode and control grid, means coupling each of elements 14to the control grid of one of tubes V301V3ll4, and two sources ofnegative bias voltage of unequal values at conductors 98 and 102. Theinvention further provides at resistor RWS means applying the lesser ofsaid bias voltages to the control grids of those tubes, and at relayK205 means responsive to the generation of a signal in an element of thearray 20 later traversed by the club head shadow to apply the greater ofsaid bias voltages to tubes V301-V314. The invention further provides athird stepping relay switch 150 having as many banks of contacts 152 to157 as there are groups of lamp circuits on the board and having twofurther banks of contacts 151 and 158, the lamp circuits of each of saidgroups being connected to the contacts of a separate one of the banks152 to 157 on stepping switch 159. The invention further provides atconductors I to 1 means connecting the contacts of a second bank ofcontacts on said first stepping switch 130 to the wiper arms of thebanks 152 to 157 on said third stepping switch to whose contacts saidlamp circuits are connected, means connecting the contacts of said twofurther banks 151 and 158 on said third stepping switch 15% to theplate-cathode conduction paths of the electron discharge tubes V301 toV314 which are coupled to the sensing elements 14 of the two arrays 18and 20 respectively such that each position of said third steppingswitch 156 connects the wiper arms of its said two further banks 151 and158 to a unique pair of the tubes V3l1 to V314. The invention furtherprovides a relay K288 having normally closed contacts 208-1 in circuitwith the stepping coil 159 of said third stepping switch 156, said relayhaving two actuating coils 2084 and 2%8-6 through both of which currentmust flow to operate that relay, the wiper arms of said two furtherbanks 151 and 158 being connected in series with said last named coilsrespectively. The invention further provides at conductors 334, 336 and338 means connecting selected even numbered contacts on a second bank125 of said second stepping switch 120 to said supplementary lampcircuits for energization thereof via the wiper arm of said last namedbank, and in relays K306, K308 and K310 it provides means responsive toselection of said associated lamp circuits T31, T48 and T35 by saidfirst and third stepping switches to de-energize said firstsupplementary lamp circuits 300, 3&2 and 394 and to energize said secondsupplementary lamp circuits 322, 32 iand 326.

The invention is however not limited to the details set forth in thepreceding paragraph nor to the structures which have been illustratedand described hereinabove. Numerous modifications may be made thereinwithout departing from the scope of the invention, which is set forth inthe appended claims.

I claim:

1. Golf practice apparatus comprising a captive ball, displaceable meansto support said ball in a rest position, means to generate a signalrepresentative of the time of passage of said ball between said restposition and a displaced position on being struck with a golf club swungthereat, two linear arrays of photo-electric sensing elements extendingtransversely of the path of the projection of the head of said club ontoa plane, said elements being arranged for the generation of a signal atone element in each of said arrays by the shadow of said swung clubhead, a plurality of groups of electrically energizable indicatingmeans, the indicating means of each of said groups being associated witha range of values for said first named signal and each indicating meanswithin each of said groups being associated with signals generated at acombination of said sensing elements, separate movable powerdistributing means for each of said groups, means responsive to saidfirst-named signal to energize one of said distributing means, and meansresponsive to signals from said one elements to set said onedistributing means to a position effecting energization of theindicating means associated with said one elements.

2. Golf practice apparatus comprising a captive ball, displaceable meansto support said ball in a rest position, means to generate a signalrepresentative of the time of passage of said ball between said restposition and a displaced position on being struck with a golf club swungthereat, two linear arrays of photo-electric sensing elements extendingtransversely of the path of the projection of the head of said club ontoa plane, said element being arranged for the generation of a signal atone element in each of said arrays by the shadow of said swung clubhead, a plurality of groups of electrically energizable indicatingmeans, a switching circuit for each of said elements closable inresponse to the generation of a signal at such element, a stepping relayswitch having a bank of contacts for each of said groups, the indicatingmeans of each group being connected to the contacts of such bank, meansto select for energization the wiper arm of one of said banks accordingto the value of said first named signal, said stepping switch having twofurther banks the contacts of each of which are connected to theswitching circuits of the sensing elements of one of said arrays suchthat each position of said stepping switch connects the wiper arms ofsaid further banks to a unique pair of said switching circuits, a relayhaving normally closed contacts in circuit with the stepping coil ofsaid stepping switch, said relay having two actuating coils through bothof which current must pass to operate said relay, the wiper arms of eachof said further banks being connected in series with one of saidlast-named coils, whereby the circuit for said stepping coil isinterrupted at said relay when the arms of said stepping switch areconnected to the switching circuits of the sensing elements at whichsignals are generated by said swung golf club.

3. In a golf practice apparatus including a captive ball, a plurality ofgroups of electrically energizable indicating means and means to developon a capacitor a charge representative of the impact delivered to saidball when struck with a golf club, means to select for energizationamong said groups in accordance with the value of said charge, saidlast-named means comprising a stepping relay switch having a pluralityof banks of contacts, an electron discharge device having a cathode,anode and control grid and having its anode-cathode path connected inseries with the stepping coil of said stepping switch and with a sourceof alternating current voltage, a plurality of resistors connected inseries between the contacts of one of said banks, said resistors beingconnected in series with a source of direct current voltage and with afurther resistor to bias said device to cutoff, and means to apply avoltage representative of said charge as an unbiasing signal to thecontrol grid of said device, whereby said stepping switch will take up aposition representative of the value of said charge.

4. A golf practice apparatus comprising a captive ball, displaceablemeans to support said ball in a rest position,

a plurality of electrically energizabl'e indicating means, two lineararrays of sensing elements extending transversely of the path of thehead of a golf club swung to strike said ball in position to betraversed successively by said club head, said elements being arrangedfor the generation of a signal on one element in each of said arrays, anelectron discharge device for each of said elements,

each of said devices including an anode, a cathode and a versed by saidclub head to apply the greater of said 15 bias voltages to said devices,and means to connect a source of voltage to combinations of saidindicating means in response to the application of unbiasing signals tocombinations of said electron discharge devices.

References Cited in the file of this patent UNITED STATES PATENTS2,102,166 Roberts Dec. 14, 1937 2,528,616 Smith Nov. 17, 1950 2,545,634Smith Mar. 20, 1951 2,571,974 Walker Oct. 16, 1951 2,783,999 SimjianMar. 5, 1957 2,825,569 Alvarez Mar. 5, 1958

